This invention relates to a belt conveyor system for continuously transporting materials.
Belt conveyors, particularly belt conveyors of the bucket type are known. Chain link drive systems with buckets or pans attached have been employed to transport materials in both a horizontal and/or vertical path. Flat belting with steel or plastic buckets has also be used commercially for this purpose for material transported in an inclined path. However, these conveyors have a number of drawbacks. Most require heavy structural support, are noisy to operate, have too many moving parts, require excessive amounts of horsepower to operate, have a high cost of maintenance and repair and are dificult to clean.
Other types of conveyors, for example as described in U.S. Pat. No. 4,019,625, have buckets which are supported by transverse elements and extend between two conveyor belts. Each conveyor belt is connected to the neighboring bucket by such transverse element, but without pivotal movement between buckets at this connection. Instead, flexture of the conveyor belts is accommodated by bending of a part of the transverse bucket walls of reduced thickness. The connection of the transverse supporting element to the respective conveyor belts is fixed.
U.S. Pat. No. 4,503,971 describes a bucket-type conveying belt having along its opposite longitudinal edges, which are transversely spaced apart, a succession of pairs of blocks in the form of guide pulleys and support pulleys. These pulleys are required to assist in the conveying operation. Traction ropes are also required to relieve the belt and to permit vertical movement of the buckets. This system is quite cumbersome to operate and maintain because of its numerous coacting parts.
In U.S. Pat. No. 3,637,091 a molded plastic belt conveyor system is provided. The system includes parallel continuous cables which are driven by driving wheels. A continuous belt disposed between the cables is connected to the cables by clip means riding thereon. The belt is indirectly driven by the driving wheels since there is no substantial contact between the clip means and the driving wheels. The subject clip means includes an offset portion, the outer end of which is provided with a generally semicylindrical groove means the bottom portion of which engages the cable normal to horizontal plane of travel of the belt permitting the clip means to ride on the cables. A vertically-extending slot is located within the upper internal portion of the semicircular groove permits the clip to be spread apart and then to grip the upper portion of the cable with a snap-like action. However, due to their open construction and the fact that the plane of attachment of the cable within the groove is normal to the horizontal plane of travel of the belt, these clips do not effectively maintain continuous engagement with the cables on which they ride. Often times, they become disengaged from the cables and/or cause the cables to be disengaged from the pulleys, causing the conveyor system to become inoperable. Attempts were made to solve this problem by attaching a spring-loaded metal tab to each clip. This tab was locked about the lower portion of the cable so that the cable and belt were not movable during use one with respect to the other. Thus, the cables and the belt could not become realigned during use causing the operation of the conveyor system to be constantly interrupted.
There is, therefore, a commercial need for a belt conveyor system of the type described above in which there can be continuous relative movement of the conveyor belt and cables in order to provide an uninterrupted transportation of materials over extended periods of time.